In classical Islamic law, a concubine was a slave-woman with whom her master engaged in sexual relations. Concubinage was widely accepted by Muslim scholars in pre-modern times. Most modern Muslims, both scholars and laypersons, believe that Islam no longer accepts concubinage and that sexual relations are religiously permissible only within marriage. With abolition of slavery in the Muslim world, the practice of concubinage came to an end. Many modern Muslims see slavery as contrary to Islamic principles of justice and equality.